Health Minutes

Health Minutes Navigation:

HRT and Alzheimer's disease

One touted benefit of oestrogen supplementation is that it may delay Alzheimer's disease, but the evidence for this is uncertain.

23 07 2002

With the current crisis around Hormone Replacement Therapy, women might be wondering about one touted benefit of oestrogen supplementation, namely that it may delay Alzheimer's disease.

The human evidence so far comes from unreliable sources: observations made almost by accident in studies looking at other aspects of women's health.

Then there's animal research, which has found that in the ageing rat brain, oestrogen increases the amount of a memory messenger on the outside of brain cells.

Now that sounds like good news. But it isn't necessarily, and that's because of the way memories are stored in the brain.

Memories are thought to be laid down by setting up patterns of nerve connections  called synapses.

So a memory of, say, a great holiday, is really an electrical imprint across thousands of these connections.

The problem is that as we age, the number of possible synapses in the brain declines. But oestrogen doesn't reverse that (in animals at least), which in turn could mean that all the memory chemicals in the world may not make a difference if the connections aren't there to be made.

So if this is true in human brains  a big 'if'  you can only expect a limited benefit from HRT.